PARP inhibitors that target PARP1/2, such as olaparib and talazoparib, have been approved as anticancer agents for patients with breast and ovarian cancers bearing mutations in the homologous recombination (HR) factors BRCA1 and BRCA2, as well as for platinum-sensitive cancers [9–12]. The gene discussed is PARP1; the disease is ovarian carcinoma.